Horsepower
12-30-2005, 11:03 PM
#1
Racer
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Horsepower
What horsepower does the 83 944 engine put out? I just bought back a Mazda RX7 GSL SE that I sold to a kid six years ago, this 13B rotary motor puts out 135 HP. It's a pretty quick and nimble car, just wondered how it compared to the 944 motor. I owned several RX7's no issues, just batteries, mufflers, they went on for ever.
Mike
Mike
12-30-2005, 11:12 PM
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From various sources, it varies from 130-150. At the flywheel, at the wheels I'd hazard a guess that it's about 100-110. This is in ideal conditions on a new motor, not a 100k beast you'd find today. But then again, you'll hear two things here.
1. It's not about horsepower, it's about torque!
2. Our cars weren't made for stoplight to stoplight...they are more comfortable "cruising" at "speed" and are happy around corners.
I've yet to drive one, when I do, you'll be sure to get my driving impressions! -The Kid
1. It's not about horsepower, it's about torque!
2. Our cars weren't made for stoplight to stoplight...they are more comfortable "cruising" at "speed" and are happy around corners.
I've yet to drive one, when I do, you'll be sure to get my driving impressions! -The Kid
12-30-2005, 11:21 PM
#3
Three Wheelin'
"1. It's not about horsepower, it's about torque!"
No!!
People always say this, but it is dead wrong. How fast a car is can be related directly to how much area is under the engine speed/horsepower curve. Torque has no effect at all on how fast a car is. A car that makes more torque will not feel faster, a car that makes more power at that point will. Thrust (the feeling that we all love when driving a fast car) comes from horsepower, not torque!
No!!
People always say this, but it is dead wrong. How fast a car is can be related directly to how much area is under the engine speed/horsepower curve. Torque has no effect at all on how fast a car is. A car that makes more torque will not feel faster, a car that makes more power at that point will. Thrust (the feeling that we all love when driving a fast car) comes from horsepower, not torque!
12-30-2005, 11:56 PM
#4
Sorry Mark.
Horsepower is Torque applied over time. Without Torque you do not have Horsepower (unless you drive a Honda
). Without Torque, you need to spin the the hell out of the motor a la S2K.
The 944s can make decent torque.
The Kid is right.
Horsepower is Torque applied over time. Without Torque you do not have Horsepower (unless you drive a Honda
). Without Torque, you need to spin the the hell out of the motor a la S2K.The 944s can make decent torque.
The Kid is right.
12-31-2005, 12:14 AM
#5
Nordschleife Master
Originally Posted by mark944turbo
"1. It's not about horsepower, it's about torque!"
No!!
People always say this, but it is dead wrong. How fast a car is can be related directly to how much area is under the engine speed/horsepower curve. Torque has no effect at all on how fast a car is. A car that makes more torque will not feel faster, a car that makes more power at that point will. Thrust (the feeling that we all love when driving a fast car) comes from horsepower, not torque!
No!!
People always say this, but it is dead wrong. How fast a car is can be related directly to how much area is under the engine speed/horsepower curve. Torque has no effect at all on how fast a car is. A car that makes more torque will not feel faster, a car that makes more power at that point will. Thrust (the feeling that we all love when driving a fast car) comes from horsepower, not torque!
What you're saying is really a matter of perspective and somewhat wrong. The area of power versus RPM is not too important. Power versus time has value and is different. Also, looking at torque versus time is a valuable technique in measuring engine output. Don't discount it.
It's kind of amusing that most dyno graphs show power and torque versus RPM. As there's a direct relationship between these (hp=torque*rpm/5250 in SAE units) the two lines are redundant. I think it's a sociological thing for people to focus on "power" as it is just more appealing than "torque."
That feeling of "thrust" is acceleration which is force divided by mass. Force is the linear version of torque. So what really matters is the torque on the rear axle. This can be firgured with comparable ease from either engine torque or horsepower.
Frankly did about 30 posts on this in another list recently. Tired of it. Please do have the last word.
12-31-2005, 12:31 AM
#6
Race Director
Hey Ian, from what I've read over the years, most 944s that aren't in poor shape generally dyno around 120-130 at the wheels.
You'll find these cars are fun with the power they have. The N/As also make you crazy for a 951
You'll find these cars are fun with the power they have. The N/As also make you crazy for a 951
12-31-2005, 12:34 AM
#7
Nordschleife Master
The thing i like about the 'under powered' (if you even want to call it that) nature of the regular 2.5L n/a engine is that its just enough power to remain fun, however keep you out of trouble (like hitting boost in mid turn). Its a great car to learn on how to go fast, not drive fast.
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12-31-2005, 12:44 AM
#8
Three Wheelin'
"Sorry Mark.
Horsepower is Torque applied over time. Without Torque you do not have Horsepower (unless you drive a Honda ). Without Torque, you need to spin the the hell out of the motor a la S2K.
The 944s can make decent torque.
The Kid is right."
The kid is not right. Why do we care about torque? Why does it matter at all? You tell me, please. If we have 2 cars, and they make the same power for the same time, they will be equally as fast. Torque is a useless number when comparing how fast 2 cars are. One could have 20000 lb ft of torque and the other 2 lb ft and if they make the same power for the same time they will accelerate right next to each other.
I know the relationship between hp and torque. I am asking why you would ever look at a torque curve instead of a power curve when comparing 2 engines, unless you want to argue about which one will last longer, which is better for towing heavy objects, other cases that mbonner does not care about.
He asked about quickness! Horsepower and vehicle weight (plus soem other stuff)!
Glen, I am sorry, I should have said hp vs time, not hp vs rpm, but given a dyno chart my point is the hp curve is what to look at when trying to find out how fast a car is, assuming the same gear ratios, weight, etc, NOT the torque curve.
http://www.yawpower.com/tqvshp.html
Notice towards the very end,
"So there it is. Horsepower is the determining factor in the rate of acceleration of any vehicle."
Horsepower is Torque applied over time. Without Torque you do not have Horsepower (unless you drive a Honda ). Without Torque, you need to spin the the hell out of the motor a la S2K.
The 944s can make decent torque.
The Kid is right."
The kid is not right. Why do we care about torque? Why does it matter at all? You tell me, please. If we have 2 cars, and they make the same power for the same time, they will be equally as fast. Torque is a useless number when comparing how fast 2 cars are. One could have 20000 lb ft of torque and the other 2 lb ft and if they make the same power for the same time they will accelerate right next to each other.
I know the relationship between hp and torque. I am asking why you would ever look at a torque curve instead of a power curve when comparing 2 engines, unless you want to argue about which one will last longer, which is better for towing heavy objects, other cases that mbonner does not care about.
He asked about quickness! Horsepower and vehicle weight (plus soem other stuff)!
Glen, I am sorry, I should have said hp vs time, not hp vs rpm, but given a dyno chart my point is the hp curve is what to look at when trying to find out how fast a car is, assuming the same gear ratios, weight, etc, NOT the torque curve.
http://www.yawpower.com/tqvshp.html
Notice towards the very end,
"So there it is. Horsepower is the determining factor in the rate of acceleration of any vehicle."
12-31-2005, 12:51 AM
#9
Three Wheelin'
Power versus time has value and is different. Also, looking at torque versus time is a valuable technique in measuring engine output. Don't discount it.
That feeling of "thrust" is acceleration which is force divided by mass.
The constant depends on a whole bunch of stuff, but the point is why would you use torque when it all simplifies to this?
12-31-2005, 01:02 AM
#12
Three Wheelin'
"The area of power versus RPM is not too important. Power versus time has value and is different."
Well I am glad Glen agrees with me here. Its not the point anyway, how about answering the real question. What does torque have to do with how fast a car is?
I dont think this is nonsense, I am not being an idiot, in my opinion I know more about this than you do Daniel, and its fun to discuss.
Well I am glad Glen agrees with me here. Its not the point anyway, how about answering the real question. What does torque have to do with how fast a car is?
I dont think this is nonsense, I am not being an idiot, in my opinion I know more about this than you do Daniel, and its fun to discuss.
12-31-2005, 01:20 AM
#15
Better yet, why don't we take a look at how an engine produces power... shall we...
The torque at the crankshaft depends,first, on the force generated piston (PA) and, second, on the angle between the rod and the crank, reaching a maximum at 90 degs when the torque will be PAS/2. where S2 is half the stroke. As both P and the crank angle avary continuously, it helps to think ofthe torquse ans a steady mean pressure and a constant mean value for the stroke/rod factor.
Torque will therefore, be a function of P, A, and S. If the engine running at speed N (RPM) it's power (HP) will be afunction of T and N. In order to increase torque it will be necessary to increase A and /orS (both of which will raise teh displacement) or increase P. In order to increase power (HP) it will be necessary to increaseT or N or both.
Basically. Power is a result of Torque applied over time. HP=TQxRPM/5252. The only way to increase HP without increasing TQ is to raise N (or RPMs). Otherwise, all modifications result in an increase in TQ which drives the change in power.
Add fuel and air? You're increasing P, wich increses TQ which increses HP....
Increase displacement? An increase in A increses TQ, which increases HP...
TQ is king.
Questions?
The torque at the crankshaft depends,first, on the force generated piston (PA) and, second, on the angle between the rod and the crank, reaching a maximum at 90 degs when the torque will be PAS/2. where S2 is half the stroke. As both P and the crank angle avary continuously, it helps to think ofthe torquse ans a steady mean pressure and a constant mean value for the stroke/rod factor.
Torque will therefore, be a function of P, A, and S. If the engine running at speed N (RPM) it's power (HP) will be afunction of T and N. In order to increase torque it will be necessary to increase A and /orS (both of which will raise teh displacement) or increase P. In order to increase power (HP) it will be necessary to increaseT or N or both.
Basically. Power is a result of Torque applied over time. HP=TQxRPM/5252. The only way to increase HP without increasing TQ is to raise N (or RPMs). Otherwise, all modifications result in an increase in TQ which drives the change in power.
Add fuel and air? You're increasing P, wich increses TQ which increses HP....
Increase displacement? An increase in A increses TQ, which increases HP...
TQ is king.
Questions?